1. Field of the Invention
The present invention relates to a laser induced thermal imaging apparatus and, more particularly, to a laser induced thermal imaging apparatus for fabricating an organic light emitting display.
2. Description of the Related Art
In general, an organic light emitting display (OLED) among flat panel displays has a fast response speed of 1 ms or less, low power consumption, and is an emissive display, so that it does not have a view angle problem and may be advantageously employed as a display medium for displaying moving pictures in regardless of its size. In addition, it may be fabricated at a low temperature and a process for fabricating the same based on the conventional semiconductor process technique is simple, so that it has been noticed as a next-generation flat panel display.
The OLED may be mainly classified into a polymer type display using a wet process and a small molecular type display using a deposition process according to a material and a process employed for an organic light emitting diode.
In the case of inkjet printing method among methods of patterning a polymer or small molecular emission layer, there exists a limit in employing the material for organic layers except the emission layer and a trouble in forming a structure for inkjet printing on a substrate. In addition, in the case of pattering the emission layer by means of a deposition process, there occurs a difficulty in fabricating a large-sized device due to a use of a metal mask.
Accordingly, a laser induced thermal imaging (LITI) method has been developed in recent years which may be employed instead of the above-described pattering methods.
The LITI method is one that converts laser generated from a light source into thermal energy, which allows a material of forming a pattern to be transferred onto a target substrate to form the pattern, and in order to perform such a method, a donor substrate where the transfer layer is formed, a light source, and a subject substrate are required. In accordance with the LITI method, the donor substrate covers the substrate being an acceptor, and the donor substrate and the substrate are fixed on a stage.
In general, the transfer layer is an organic layer which is very sensitive to oxygen and vapor. That is, when the organic layer is exposed to the oxygen or the vapor, lifetime of the organic layer is degraded, or luminous efficiency and lifetime are degraded when the organic layer includes an emission layer. The lifetime and the luminous efficiency of the organic light emitting display may be adversely affected, so that it is essential to consider an atmosphere within an apparatus where the transfer procedure is carried out.